(1) Field of the Invention:
The present invention relates to a method for modifying the surface of polycarbonate resin, particularly, the surface of diethylene glycol bis(allyl carbonate) copolymer resin.
(2) Related Art Statement:
Diethylene glycol bis(allyl carbonate) copolymer resin (hereinafter referred to as ADC resin) is a transparent thermosetting resin having excellent optical properties and mechanical properties, and is used as a lens for glasses and the like (Kogyo Zairyo, Vol. 25, No. 3, pages 35-37 (1977), and U.S. Pat. No. 2,370,565). ADC resin is different from polymethacrylate resin and can be easily dyed in the optician shop (Kindai Megane, 1977, May, pages 118-129).
However, the dye capable of being used effectively in the dyeing in the optician shop is limited to a dispersant dye, and moreover the dispersant dye solution must be used at a high temperature of at least 90.degree. C.
ADC resin has not hitherto been able to be dyed with an acid dye. When ADC resin is dyed with a commonly used dispersant dye, the dyed ADC resin absorbs not only a light having a specific wavelength, but also light having wavelengths in the vicinity of the specific wavelength. Therefore, the ADC resin dyed with a dispersant dye has a broad transmittance curve. Such dyed resin can not satisfactory be used in an industrial instrument requiring a high vividness of color. Particularly, liquid crystal is recently used in the OA instrument and indicator, and hence the colored sheet or dyed sheet to be used in these instruments is demanded to have a sharp transmittance curve.
The inventors have made various investigations and experiments, and found out that an ADC resin having excellent dyeability and being able to be dyed with acid dye can be obtained by modifying the surface of the ADC resin, and accomplished the present invention.